A known image forming apparatus includes a known roller device that includes a pickup roller, a sheet separating roller, a holding member, and a main body. The pickup roller is configured to feed one or more sheets from a sheet feed tray. The sheet separating roller is disposed downstream of the pickup roller with respect to a sheet conveying direction. The holding member is configured to rotatably hold the pickup roller and the sheet separating roller. The main body is configured to receive the holding member that is attachable to the main body. The pickup roller is rotatably held by a pair of side walls of the holding member.